require "os/linux/glibc"

class LlvmAT8 < Formula
  desc "Next-gen compiler infrastructure"
  homepage "https://llvm.org/"
  url "https://github.com/llvm/llvm-project/releases/download/llvmorg-8.0.1/llvm-8.0.1.src.tar.xz"
  sha256 "44787a6d02f7140f145e2250d56c9f849334e11f9ae379827510ed72f12b75e7"
  license "NCSA"
  revision OS.mac? ? 3 : 4

  bottle do
    cellar :any
    sha256 "ab099d84e5f0a58ea37172fd85753336d855fc25e9459ceff12ddc2dbb56ef71" => :catalina
    sha256 "ee795cbebce64f79bbcf7c42526093df7bd2e5e986a721197bca5cf6c822e87a" => :mojave
    sha256 "3f80b7119307b128b1e3ae8a2fea97a9878afb5a7436a7d35615b1e743bc7622" => :high_sierra
    sha256 "f8d4d3f94d03df55400c31c7ba9f81fc25dfa3cf0ad67c172e04328109a56c4a" => :x86_64_linux
  end

  # Clang cannot find system headers if Xcode CLT is not installed
  pour_bottle? do
    reason "The bottle needs the Xcode CLT to be installed."
    satisfy { !OS.mac? || MacOS::CLT.installed? }
  end

  keg_only :versioned_formula

  # https://llvm.org/docs/GettingStarted.html#requirement
  depends_on "cmake" => :build
  depends_on xcode: :build if OS.mac?
  depends_on "libffi"
  depends_on "swig"

  unless OS.mac?
    depends_on "gcc" # needed for libstdc++
    if Formula["glibc"].any_version_installed? || OS::Linux::Glibc.system_version < Formula["glibc"].version
      depends_on "glibc"
    end
    depends_on "binutils" # needed for gold and strip
    depends_on "libedit" # llvm requires <histedit.h>
    depends_on "libelf" # openmp requires <gelf.h>
    depends_on "ncurses"
    depends_on "libxml2"
    depends_on "zlib"
    depends_on "python@3.8"
  end

  resource "clang" do
    url "https://github.com/llvm/llvm-project/releases/download/llvmorg-8.0.1/cfe-8.0.1.src.tar.xz"
    sha256 "70effd69f7a8ab249f66b0a68aba8b08af52aa2ab710dfb8a0fba102685b1646"

    unless OS.mac?
      patch do
        url "https://gist.githubusercontent.com/iMichka/a5d88f6bbe1f62fc43dc040282234452/raw/430616d646260e47360d9cba0901ac2876007350/clang8?full_index=1"
        sha256 "a7403c5a3ea2edddb7c1cb70274396f4c31d6b7c37aa1e4e4edaca3d1b78300f"
      end
    end
  end

  resource "clang-extra-tools" do
    url "https://github.com/llvm/llvm-project/releases/download/llvmorg-8.0.1/clang-tools-extra-8.0.1.src.tar.xz"
    sha256 "187179b617e4f07bb605cc215da0527e64990b4a7dd5cbcc452a16b64e02c3e1"
  end

  resource "compiler-rt" do
    url "https://github.com/llvm/llvm-project/releases/download/llvmorg-8.0.1/compiler-rt-8.0.1.src.tar.xz"
    sha256 "11828fb4823387d820c6715b25f6b2405e60837d12a7469e7a8882911c721837"
  end

  resource "libcxx" do
    url "https://github.com/llvm/llvm-project/releases/download/llvmorg-8.0.1/libcxx-8.0.1.src.tar.xz"
    sha256 "7f0652c86a0307a250b5741ab6e82bb10766fb6f2b5a5602a63f30337e629b78"
  end

  resource "libcxxabi" do
    url "https://llvm.org/releases/6.0.1/libcxxabi-6.0.1.src.tar.xz"
    sha256 "209f2ec244a8945c891f722e9eda7c54a5a7048401abd62c62199f3064db385f"
  end

  resource "libunwind" do
    url "https://github.com/llvm/llvm-project/releases/download/llvmorg-8.0.1/libunwind-8.0.1.src.tar.xz"
    sha256 "1870161dda3172c63e632c1f60624564e1eb0f9233cfa8f040748ca5ff630f6e"
  end

  resource "lld" do
    url "https://github.com/llvm/llvm-project/releases/download/llvmorg-8.0.1/lld-8.0.1.src.tar.xz"
    sha256 "9fba1e94249bd7913e8a6c3aadcb308b76c8c3d83c5ce36c99c3f34d73873d88"
  end

  resource "lldb" do
    url "https://github.com/llvm/llvm-project/releases/download/llvmorg-8.0.1/lldb-8.0.1.src.tar.xz"
    sha256 "e8a79baa6d11dd0650ab4a1b479f699dfad82af627cbbcd49fa6f2dc14e131d7"
  end

  resource "openmp" do
    url "https://github.com/llvm/llvm-project/releases/download/llvmorg-8.0.1/openmp-8.0.1.src.tar.xz"
    sha256 "3e85dd3cad41117b7c89a41de72f2e6aa756ea7b4ef63bb10dcddf8561a7722c"
  end

  resource "polly" do
    url "https://github.com/llvm/llvm-project/releases/download/llvmorg-8.0.1/polly-8.0.1.src.tar.xz"
    sha256 "e8a1f7e8af238b32ce39ab5de1f3317a2e3f7d71a8b1b8bbacbd481ac76fd2d1"
  end

  def install
    # Apple's libstdc++ is too old to build LLVM
    ENV.libcxx if ENV.compiler == :clang

    (buildpath/"tools/clang").install resource("clang")
    (buildpath/"tools/clang/tools/extra").install resource("clang-extra-tools")
    (buildpath/"projects/openmp").install resource("openmp")
    (buildpath/"projects/libcxx").install resource("libcxx") if OS.mac?
    (buildpath/"projects/libunwind").install resource("libunwind")
    (buildpath/"tools/lld").install resource("lld")
    (buildpath/"tools/lldb").install resource("lldb")
    (buildpath/"tools/polly").install resource("polly")
    (buildpath/"projects/compiler-rt").install resource("compiler-rt")

    # compiler-rt has some iOS simulator features that require i386 symbols
    # I'm assuming the rest of clang needs support too for 32-bit compilation
    # to work correctly, but if not, perhaps universal binaries could be
    # limited to compiler-rt. llvm makes this somewhat easier because compiler-rt
    # can almost be treated as an entirely different build from llvm.
    ENV.permit_arch_flags

    unless OS.mac?
      # see https://llvm.org/docs/HowToCrossCompileBuiltinsOnArm.html#the-cmake-try-compile-stage-fails
      # Basically, the stage1 clang will try to locate a gcc toolchain and often
      # get the default from /usr/local, which might contains an old version of
      # gcc that can't build compiler-rt. This fixes the problem and, unlike
      # setting the main project's cmake option -DGCC_INSTALL_PREFIX, avoid
      # hardcoding the gcc path into the binary
      inreplace "projects/compiler-rt/CMakeLists.txt", /(cmake_minimum_required.*\n)/,
        "\\1add_compile_options(\"--gcc-toolchain=#{Formula["gcc"].opt_prefix}\")"
    end

    args = %W[
      -DLIBOMP_ARCH=x86_64
      -DLINK_POLLY_INTO_TOOLS=ON
      -DLLVM_BUILD_EXTERNAL_COMPILER_RT=ON
      -DLLVM_BUILD_LLVM_DYLIB=ON
      -DLLVM_ENABLE_EH=ON
      -DLLVM_ENABLE_FFI=ON
      -DLLVM_ENABLE_RTTI=ON
      -DCLANG_ANALYZER_ENABLE_Z3_SOLVER=OFF
      -DLLVM_INCLUDE_DOCS=OFF
      -DLLVM_INSTALL_UTILS=ON
      -DLLVM_OPTIMIZED_TABLEGEN=ON
      -DLLVM_TARGETS_TO_BUILD=all
      -DWITH_POLLY=ON
      -DFFI_INCLUDE_DIR=#{Formula["libffi"].opt_lib}/libffi-#{Formula["libffi"].version}/include
      -DFFI_LIBRARY_DIR=#{Formula["libffi"].opt_lib}
      -DLLDB_USE_SYSTEM_DEBUGSERVER=ON
      -DLLDB_DISABLE_PYTHON=1
      -DLIBOMP_INSTALL_ALIASES=OFF
    ]
    if OS.mac?
      args << "-DLLVM_CREATE_XCODE_TOOLCHAIN=ON"
      args << "-DLLVM_ENABLE_LIBCXX=ON"
    else
      args << "-DLLVM_CREATE_XCODE_TOOLCHAIN=OFF"
      args << "-DLLVM_ENABLE_LIBCXX=OFF"
      args << "-DCLANG_DEFAULT_CXX_STDLIB=libstdc++"
    end

    # Enable llvm gold plugin for LTO
    args << "-DLLVM_BINUTILS_INCDIR=#{Formula["binutils"].opt_include}" unless OS.mac?

    if OS.mac? && MacOS.version >= :mojave
      sdk_path = MacOS::CLT.installed? ? "/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk" : MacOS.sdk_path
      args << "-DDEFAULT_SYSROOT=#{sdk_path}"
    end

    mkdir "build" do
      system "cmake", "-G", "Unix Makefiles", "..", *(std_cmake_args + args)
      system "make"
      system "make", "install"
      system "make", "install-xcode-toolchain" if OS.mac?
    end

    (share/"clang/tools").install Dir["tools/clang/tools/scan-{build,view}"]
    (share/"cmake").install "cmake/modules"
    inreplace "#{share}/clang/tools/scan-build/bin/scan-build", "$RealBin/bin/clang", "#{bin}/clang"
    bin.install_symlink share/"clang/tools/scan-build/bin/scan-build", share/"clang/tools/scan-view/bin/scan-view"
    man1.install_symlink share/"clang/tools/scan-build/man/scan-build.1"

    # install llvm python bindings
    xz = OS.mac? ? "2.7": "3.8"
    (lib/"python#{xz}/site-packages").install buildpath/"bindings/python/llvm"
    (lib/"python#{xz}/site-packages").install buildpath/"tools/clang/bindings/python/clang"

    unless OS.mac?
      # Strip executables/libraries/object files to reduce their size
      system("strip", "--strip-unneeded", "--preserve-dates", *(Dir[bin/"**/*", lib/"**/*"]).select do |f|
        f = Pathname.new(f)
        f.file? && (f.elf? || f.extname == ".a")
      end)
    end
  end

  def caveats
    <<~EOS
      To use the bundled libc++ please add the following LDFLAGS:
        LDFLAGS="-L#{opt_lib} -Wl,-rpath,#{opt_lib}"
    EOS
  end

  test do
    assert_equal prefix.to_s, shell_output("#{bin}/llvm-config --prefix").chomp

    (testpath/"omptest.c").write <<~EOS
      #include <stdlib.h>
      #include <stdio.h>
      #include <omp.h>
      int main() {
          #pragma omp parallel num_threads(4)
          {
            printf("Hello from thread %d, nthreads %d\\n", omp_get_thread_num(), omp_get_num_threads());
          }
          return EXIT_SUCCESS;
      }
    EOS

    clean_version = version.to_s[/(\d+\.?)+/]

    system "#{bin}/clang", "-L#{lib}", "-fopenmp", "-nobuiltininc",
                           "-I#{lib}/clang/#{clean_version}/include",
                           *("-Wl,-rpath=#{lib}" unless OS.mac?),
                           "omptest.c", "-o", "omptest", *ENV["LDFLAGS"].split
    testresult = shell_output("./omptest")

    sorted_testresult = testresult.split("\n").sort.join("\n")
    expected_result = <<~EOS
      Hello from thread 0, nthreads 4
      Hello from thread 1, nthreads 4
      Hello from thread 2, nthreads 4
      Hello from thread 3, nthreads 4
    EOS
    assert_equal expected_result.strip, sorted_testresult.strip

    (testpath/"test.c").write <<~EOS
      #include <stdio.h>
      int main()
      {
        printf("Hello World!\\n");
        return 0;
      }
    EOS

    (testpath/"test.cpp").write <<~EOS
      #include <iostream>
      int main()
      {
        std::cout << "Hello World!" << std::endl;
        return 0;
      }
    EOS

    unless OS.mac?
      system "#{bin}/clang++", "-v", "test.cpp", "-o", "test"
      assert_equal "Hello World!", shell_output("./test").chomp
    end

    if OS.mac?
      # Testing default toolchain and SDK location.
      system "#{bin}/clang++", "-v",
             "-std=c++11", "test.cpp", "-o", "test++"
      assert_includes MachO::Tools.dylibs("test++"), "/usr/lib/libc++.1.dylib"
      assert_equal "Hello World!", shell_output("./test++").chomp
      system "#{bin}/clang", "-v", "test.c", "-o", "test"
      assert_equal "Hello World!", shell_output("./test").chomp

      # Testing Command Line Tools
      if MacOS::CLT.installed?
        toolchain_path = "/Library/Developer/CommandLineTools"
        sdk_path = "/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk"
        system "#{bin}/clang++", "-v",
               "-isysroot", sdk_path,
               "-isystem", "#{toolchain_path}/usr/include/c++/v1",
               "-isystem", "#{toolchain_path}/usr/include",
               "-isystem", "#{sdk_path}/usr/include",
               "-std=c++11", "test.cpp", "-o", "testCLT++"
        assert_includes MachO::Tools.dylibs("testCLT++"), "/usr/lib/libc++.1.dylib"
        assert_equal "Hello World!", shell_output("./testCLT++").chomp
        system "#{bin}/clang", "-v", "test.c", "-o", "testCLT"
        assert_equal "Hello World!", shell_output("./testCLT").chomp
      end

      # Testing Xcode
      if MacOS::Xcode.installed?
        system "#{bin}/clang++", "-v",
               "-isysroot", MacOS.sdk_path,
               "-isystem", "#{MacOS::Xcode.toolchain_path}/usr/include/c++/v1",
               "-isystem", "#{MacOS::Xcode.toolchain_path}/usr/include",
               "-isystem", "#{MacOS.sdk_path}/usr/include",
               "-std=c++11", "test.cpp", "-o", "testXC++"
        assert_includes MachO::Tools.dylibs("testXC++"), "/usr/lib/libc++.1.dylib"
        assert_equal "Hello World!", shell_output("./testXC++").chomp
        system "#{bin}/clang", "-v",
               "-isysroot", MacOS.sdk_path,
               "test.c", "-o", "testXC"
        assert_equal "Hello World!", shell_output("./testXC").chomp
      end

      # link against installed libc++
      # related to https://github.com/Homebrew/legacy-homebrew/issues/47149
      system "#{bin}/clang++", "-v",
             "-isystem", "#{opt_include}/c++/v1",
             "-std=c++11", "-stdlib=libc++", "test.cpp", "-o", "testlibc++",
             "-L#{opt_lib}", "-Wl,-rpath,#{opt_lib}"
      assert_includes MachO::Tools.dylibs("testlibc++"), "#{opt_lib}/libc++.1.dylib"
      assert_equal "Hello World!", shell_output("./testlibc++").chomp

      (testpath/"scanbuildtest.cpp").write <<~EOS
        #include <iostream>
        int main() {
          int *i = new int;
          *i = 1;
          delete i;
          std::cout << *i << std::endl;
          return 0;
        }
      EOS
      assert_includes shell_output("#{bin}/scan-build --use-analyzer #{bin}/clang++ clang++ scanbuildtest.cpp 2>&1"),
        "warning: Use of memory after it is freed"

      (testpath/"clangformattest.c").write <<~EOS
        int    main() {
            printf("Hello world!"); }
      EOS
      assert_equal "int main() { printf(\"Hello world!\"); }\n",
        shell_output("#{bin}/clang-format -style=google clangformattest.c")
    end
  end
end
